Hydrocarbon conversion



Relative Activiiy June 22, 1965 D, G. WALKER ETAL 3,190,940

HYDROCARBON CONVERSION Filed June 8, 1962 3 Sheets-Sheet 1 M01. Frucrion Al Br In Catalyst Phase or [Al Br /Al Br +Me O,A|Br 0 .2 .3 .4 .5 .s .7 .8 .9 1.0

Me O AlBr (Lewis buse/ Lewis acid) FIG. I.

INVENTORS. DAVID G. WALKER, HENRY A- HOLCOMB,

June 22, 1965 D. e. WALKER ETAL 3,190,940

HYDROCARBON CONVERSION Filed June 8, 1962 3 Sheets-Sheet 2 .Effect of Benzene on, AlBr --Me O Catalyst E 2.0 4 g z 2 2 r: J, |.5 3 .E Z v w 0 C 2 0 Lo f 2 g 2 Y X l m 0 l 3 5 7 9 1| l3 l5 Bufch Number Effect of Benzene on FIG- 3- AIBr Me O Catalyst 5 r I.- 2 Z D O O 2.0 4

1v c .2 I, g -oe O 2 m, 2 o G) 0: o

Batch Number INVENTORS.

DAVID e. WALKER, HENRY A- HOLCOMB, BY BOYD N. HILL,

ATTORNEY.

June 22, 1965 Filed June 8, 1962 Relative Catalyst Acfiv iiy 3 Sheets-Sheet 3 Effect of Benzene on AlBr H PO Cqiulyst z 5 5 a U 8 n. I C 4 cu C ID N C Batch Number FIG. 4.

INVENTORS.

DAVID G- WALKER, HENRY A. HOLCOMB, BOYD N. HI L ATTORNEY.

United States Patent 3,190,940 HYDRGCARBON CONVERSEON David G. (Walker, Henry A. Holcomb, and Boyd N. Hill, Baytown, Tern, assignors, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, N.J., a corporation of Delaware Filed June 8, 1962, Ser. No. 200,994 3 Claims. (Cl. 260683.75)

This invention relates generally to a novel catalyst system for use in hydrocarbon conversion processes. More particularly, the invention relates to a process and catalyst system for use therewith for converting hydrocarbons to isomers thereof and especially to converting paraffinic hydrocarbons to iso-parafiins.

This application is a continuation-in-part of applications Ser. Nos. 781,125 and 781,126 entitled Hydrocarbon Conversion and Isomerization Process, respectively, both filed December 17, 1958, by D. G. Walker, H. A. Holcomb, and B. N. Hill both of which applications are now abandoned.

The particular active conversion catalyst system of the invention comprises a reacted Group III-b metal halide and a free Group III-b metal halide; the reacted Group III-b metal halide comprises the combination of a Group III-b metal halide and a component containing atoms with at least one unshared pair of electrons and basic as a Lewis base to Group III-b metal halides, the Group III-b metal halides being acid as a Lewis acid. The Lewis base component and the Lewis acid Group III-b metal halide being employed in relative amounts in the catalyst phase such that the Lewis base site to Lewis acid site ratio is in the range from about 0.30 to 0.65 Lewis base sites to one Lewis acid site, with an optimum ratio of 0.45 to one.

A Lewis acid is any molecule radical or ion in which the normal electron grouping about some atom is incomplete so that the atom can accept an electron pair or' pairs. Correspondingly, a Lewis base is a structure containing an atom which is capable of donating an electron pair.

' When this particular catalyst system is used under isomerization conditions, an improved isomerization process for converting straight chain paraflinic hydrocarbons, especiallythe lower members of the series such as normal butane, normal pentane, normal hexane, normal heptane, etc., to corresponding iso-parafiins such as isobutane, iso-pentane, iso-hexane, iso-heptane, etc., results. High levels of catalyst activity for isomerization of the saturated hydrocarbons are obtained in this process; the catalyst system is essentially inactive for the promotion of cracking, disproportionation, and other side reactions;

it overcomes the adverse effects of aromatic hydrocarbons in the isomerization feed; and additionally, the catalyst system shows good activity maintenance.

The Lewis base components or co-catalysts of the invention consist of methylether, phosphoric acid, or phosphorus pentoxide. Aluminum bromide is the preferred Group III-b metal halide to be used.

These particular co-catalysts are efiective for the specific isomerization of normal parafiins in the presence of aromatic hydrocarbons.

Benzene and other aromatics (even in small concentrations of about 0.1 volume percent) inhibit seriously the activity of promoted aluminum halide catalyst for the specific isomerization of normal paraflins.

However, it has been found that aromatics in the isomerization feed stock are tolerated when the isomerization process is conducted utilitzing these particular co-catalysts. They resist the inhibitory effect of the aromatics Patented June 22, 1965 to the isomerization conversion process while the aromatics remain substantially unaltered.

The experiments illustrating the invention were conducted as liquid phase sludge type catalysis.

When aluminum bromide is used as the Group III-b metal halide, an isomerization catalyst is obtained which is active for the specific isomerization of normal butane and higher molecular weight parafins at temperatures in the range of 32 to F. When aluminum chloride is used as the Group III-b metal halide, an isomerization catalyst is obtained which is active for the isomerization of normal butane and higher molecular weight parafiins at temperatures in the range of 70 to F.

Accordingly, a primary object of the present invention is to provide a novel hydrocarbon conversion catalyst. An additional object of the present invention is to provide a process for the specific isomerization of normal parafiins. A further object of this invention is to provide a process for the specific isomerization of normal parafiins wherein the isomerization feed stock contains aromatics.

These and other objects and advantages of the invention will become apparent from the following description taken in conjunction with the drawings wherein:

FIG. 1 illustrates the relative catalyst activity when the relative amounts of methyl ether relative to aluminum bromide are varied;

FIGS. 2 and 3 show curves illustrating the effect of benzene on a dimethyl ether-aluminum bromide catalyst in the isomerization of parafiin hydrocarbons; and

FIG. 4 shows curves illustrating the effect of benzene on a phosphoric acid-aluminum bromide catalyst.

The following experimental data illustrate the practice of the invention. In the experiments aluminum bromide was added to a normal hexane feed composition contained in a reaction vessel. A-fter brief stirring, a cocatalyst was added slowly with stirring. At the end of the reaction period, the hydrocarbon layer was separated from the sludge water, washed several times and analyzed by gas partition chromatography.

In the experiments shown in Tables I and II except for the run conducted with phosphorus pentoxide, the normal hexane feed in volume percent was 0.1 isobutane, 0.3 2,3-dirnethylbutane, 0.8 2 and S-methylpentane, 96.2 normal hexane, and 2.6 methylcyclopentane. The phosphorus pentoxide run feed composition was in volume percent 0.1 2,2-dimethylbutane, 0.3 2,3-dimethylbutane and 2-methylpentane, 0.4 3-methylpentane, 84.4 normal hexane, 2.0 methylcyclopentane, and 12.8 cyclohexane.

The temperature of the reaction, the time of reaction, the co-catalyst to catalyst ratio (Lewis base site to Lewis acid site) in the catalyst phase, the product analysis, the amount of feed, and the amount of catalyst are shown for each experiment.

The data of Table I are plotted in FIG. 1. These data and the resulting curve were obtained by varying the amount of a co-catalyst, methylether, to a catalyst, aluminum bromide. Both the Lewis base site to Lewis acid site ratios and the mol fractions of Al Br in the catalyst phase are plotted in this figure.

Thus, it is seen that by varying the ratios of Lewis base site to Lewis acid site in the catalyst phase, a substantially increased catalyst activity is obtained in the range of from about 0.3 to 0.65 as indicated by the arrowed line in the figure. An optimum Lewis base site to Lewis acid site is shown to be about 0.45.

' I Table 1 A B o D E F G H Temp F 73 7s 78 78 7s 7s 7s 7s Reactlon time (hr 1 1 1 1 1 1 1 1 M01 feed/mol totalc 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 Methyl ether/AlBrg ratio in c phase 0.0 0. 32 0.40 0. 53 0.57 0.61 0.81 1.0

Product analysis, mol percent Component:

H'mmne 2,2-di1nethylbutane 0. 9 1. 1. 0 1. 0 1. 0 2,3-dimethylbutane+2-methylpent 1.0 10.3 12.8 12.4 12.8 12.9 1.5 0.1 0.4 3:6 4.3 4.3 4.2 4.5 0.0 0.7 95.2 91.1 77.7 78.1 77.7 77.5 03.0 95.5 2.2 1.0 0.0 0.2 0.2 1.7 2.8 Oyclohexane 1. 2 4. 0 3. 7 3. 9 3. 7 3. 9 2. 1 0. 2 F a 0.5 0.2 0.5 0.5 0.6 Relatlve activity; .005 0.158 0.204 0.206 0.210 0.159 .013. .000

the Lewis base site to Lewis acid site ratio is -within the Table III. range of 0.30 to 0.65. 1

110-115 110-115 110-115 Table II 1 hr. successive baton treats 0 A B o D l ane 0.300 0.300 0.300 Methylcyclopentane. 0. 037 0. 036 0. 036 Benzene 0. 015 0.034 0. 034 Temp. F. .78 32. 110-115 110-115 Ca y t, a o Reaction time (hrs) 3. 0 4. 0 1 1 Aluminum bromide 0. 247 n-Hexane feed, 1111... 150 75 46 46 Methylether 0.1235 (Jo-catalyst, g. moL- 0. 152 1 0.077 .124 8 0. 97 Phosphoric acid (96%).- AlBr3, g. mol 0. s 0. 154 .247 0. 247 I Ratlo (Lewis base/Lewis'acid) in v a lys phase 0.5 0.5 0. 50 0.39 30 It is seen in FIGS. 2;, 3, and 4 thatthe relative c taly activity approaches a constant value (thesohd lme curves) Product analys s, mol percent as the percent of benzene in the productapproaches a Com onent; constant value (the dashed line curves). Thus, these co. Isobutane 7.7 0.0 catalysts tolerate the benzene in the feed, and although the Normal butane. 0.3 0.0 h 1 1 f M catalysts .1n1t1ally decrease 1n ac why, a. 1g eve 0 l De I catalyst activity is maintainedthereafter. Cyclopentane 0.4 0.0 1 2,2-dimethylbutane 40.2 8.5 .2 .0 In Table IV data are shown for s1m1 ar experlments em- 2,3-dimethylbutane-l- 2m 1 a h u ylpemne 3&6 29'9 p y ng e y ether, ph p pn 1 or 3-methy1pentane-- 3.3 8.9 10.3 1. pentoxldeas co-catalysts 1n which an aromatic hydrocar- Normal hexane 2.9 45.9 5.5 12.3 Methylcyclopenmne 0.2 L 6 1. 6 Q bon 1s employed 1n the feed. The relative amounts of the gyclohleililane 0,-4 2.9 13.4 12,3 co-catalysts and catalyst 1n the catalyst phase are such -or1na'etane 0.5

2.;h th 1hp3 'fip that the Lewis base s1te to Lewis. acld s te who 1s w1th1n 3-methylhemne 2.5 the range of 0.30 to 0.65.. The compositions of the feed g gjf fi' ggffgfigtf 1% in volume percents for the dimethyl ether run A and for 2,2,3-trimethylbutane 0.9 the phosphoric: acid runs were 84.8% normalhhexane, 8.7% methylcyclopentane, and 6.5%; benzene. The..di-,

'- Methy1ether. 2 Phosphoric acid.

3 Phosphorus pentoxide.

A similar series' of experiments but employing an aromatic hydrocarbon in the feed, the conditions for which are shown in-Table III and the results of which are shown in FIGS. 2, 3,' and 4, were performed.

methyl ether B run feed composition in volume percents was 87.6% normal hexane, 9.4% methylcyclopentane, and 3% benzene; and the phosphorus pentoxide run feed composition in volume percents was 83.5% normalhexane, 2.5% methylcyclopentane, 8% cyclohexane, and 6% benzene.

Table IV A B C D E 13 Temp., F -115 110-115 110 110 110 110 Reaction time (hrs) 1 2 3 4 (Jo-catalyst, g. 111015. 1 0.1235 1 0.1235 082 O82 0R2 097 AlBra, g. mo1s '0. 247 0. 247 0. 247 0.247 0. 247 0. 247 Feed, g. mols. 0. 370 0. 354 0. 370 0.370 0.370 0.300 Benzene, vol. percent- 6. 5 3.0 0. 5 6. 5 6. 5 .6 Ratio 0. 5 0. 5 0. 33 0. 33 0.33 0. 4

Product analysis, mol percent Components: 5

Pentane Minus 0 0 0 0 0. 1 0.1 2,2-din1ethylbutane 17. 2 18. 2 10. 9 25. 8 35.10 30. 0

2,3-dimethylpentane+2- Inethy1pentane 40. 8 41. 2 30. 7 33.9 30.0 31. 7 '3-methy1pentane. 14. 0 14. 4 11. 4 12. 5 11.2 11.5 Normal hexan'c 14.0 13. 4 30. 6 11. 2 6. 5 8. 9 f I 'Methylcyclopentane- 1. 5 1.4 1. 5 1. 8 2. 0 1. 8 Cyclohexane 10. 7 10.7 12. 4 13. 4 14. 5 14. 7 Benzene -Q 1. 8 0. 7 2. 5 1. 4 0. 7 1. 3

1 (CHQQO. 2 H3P0 3 P105. 4 Lewis base/Lewis acid in catalyst phase.

In the preceding tables the concentration of 2,2-dimethylbutane in the hexane isomers is a good measure of the extent of isomerization because it is the predominant of the paraffin hexanes at equilibrium, and it is also the slowest isomer to approach equilibrium when normal hexane is isomerized. A criterion for specific isomerization is the amount of 2,2-dimethylbut-ane with respect to the amount of non-hexane material produced. As seen in Tables II and IV, the amount of 2,2-dimethylbutane produced is large relative to the amount of nonhexane material produced and thus good specific isomerization was obtained in these experiments.

Although the experimental runs were conducted employing normal hexane as the feed stock for the isomerization process, the invention is not to be considered as limited thereto. For example, normal parafinic hydrocarbons which may be converted into iso-paraffinic hydrocarbons by the present process include normal butame and higher boiling parafiinic hydrocarbons of the straight chain structure.

Having fully described the objects and method of operation of the invention, 'we claim:

'1. A hydrocarbon isomerization process for isomerizing par-atfinic hydrocarbons to the isomers thereof in the presence of aromatics comprising reacting a normal paraffinic hydrocarbon feed stock containing aromatic hydrocarbons in amounts from about 0.1 to about 6.5 volume percent and cycloparafiins with a catalyst under isomerization conditions, said catalyst consisting of phosphorus pentoxide and aluminum halide in a mol ratio, respectively, of 0.30 to 0.65, said catalyst in said process being resistant to the inhibitory efifect of the aromatic to the isomerization process and the aromatics remaining substantially unaltered during said isomerization process.

2. A hydrocarbon isomerization process comprising reacting under .isomerization conditions a substantially normal paratfinic hydrocarbon feedstock containing cycloparaflinic hydrocarbons and consisting essentially of hydrocarbons having 4 to 7 carbon atoms per molecule with an aluminum halide catalyst and a phosphorus pentoxide oocatalyst, the mol ratio of the phosphorus pentoxide to aluminum halide being in the range from about 0.30 to 0.65.

3. A hydrocarbon isomeriz-ation catalyst system consisting essentially of an aluminum halide catalyst and a phosphorus pen-toxide cocata-lyst, the mol ratio of the phosphorus pent-oxide to the aluminum halide being in the range from about 0.30 to 0.65.

References Cited by the Examiner UNITED STATES PATENTS 2,358,011 9/44 Ipatiefl et al 260-68375 2,389,250 11/45 Francis et al. 2606 83.75 2,468,746 5/49 Greensfelder et al. 260683.76

ALPHONSO D. SULLIVAN, Primary Examiner. 

1. A HYDROCARBON ISOMERIZATION PROCESS FOR ISOMERIZING PARAFFINIC HYDROCARBONS TO THE ISOMERS THEREOF IN THE PRESENCE OF AROMATICS COMPRISING REACTING A NORMAL PARAFFINIC HYDROCARBON FEED STOCK CONTAINING AROMATIC HYDROCARBONS IN AMOUNTS FROM ABOUT 0.1 TO ABOUT 6.5 VOLUME PERCENT AND CYCLOPARAFFINS WITH A CATALYST UNDER ISOMERIZATION CONDITIONS, SAID CATALYST CONSISTING OF PHOSPHOROUS PENTOXIDE AND ALUMINUM HALIDE IN A MOL RATIO, RESPECTIVELY, OF 0.30 TO 0.65, SAID CATALYST IN SAID PROCESS BEING RESISTANT TO THE INHIBITORY EFFECT OF THE AROMATIC TO THE ISOMERIZATION PROCESS AND THE AROMATICS REMAINING SUBSTANTIALLY UNALTERED DURING SAID ISOMERIZATION PROCESS. 